Minimum-norm cortical source estimation in layered head models is robust against skull conductivity error

dc.contributorAalto-yliopistofi
dc.contributorAalto Universityen
dc.contributor.authorStenroos, Mattien_US
dc.contributor.authorHauk, Olafen_US
dc.contributor.departmentBECSen
dc.date.accessioned2017-05-11T09:06:52Z
dc.date.available2017-05-11T09:06:52Z
dc.date.issued2013en_US
dc.description.abstractThe conductivity profile of the head has a major effect on EEG signals, but unfortunately the conductivity for the most important compartment, skull, is only poorly known. In dipole modeling studies, errors in modeled skull conductivity have been considered to have a detrimental effect on EEG source estimation. However, as dipole models are very restrictive, those results cannot be generalized to other source estimation methods. In this work, we studied the sensitivity of EEG and combined MEG + EEG source estimation to errors in skull conductivity using a distributed source model and minimum-norm (MN) estimation. We used a MEG/EEG modeling set-up that reflected state-of-the-art practices of experimental research. Cortical surfaces were segmented and realistically-shaped three-layer anatomical head models were constructed, and forward models were built with Galerkin boundary element method while varying the skull conductivity. Lead-field topographies and MN spatial filter vectors were compared across conductivities, and the localization and spatial spread of the MN estimators were assessed using intuitive resolution metrics. The results showed that the MN estimator is robust against errors in skull conductivity: the conductivity had a moderate effect on amplitudes of lead fields and spatial filter vectors, but the effect on corresponding morphologies was small. The localization performance of the EEG or combined MEG + EEG MN estimator was only minimally affected by the conductivity error, while the spread of the estimate varied slightly. Thus, the uncertainty with respect to skull conductivity should not prevent researchers from applying minimum norm estimation to EEG or combined MEG + EEG data. Comparing our results to those obtained earlier with dipole models shows that general judgment on the performance of an imaging modality should not be based on analysis with one source estimation method only.en
dc.description.versionPeer revieweden
dc.format.extent265–272
dc.format.mimetypeapplication/pdfen_US
dc.identifier.citationStenroos, M & Hauk, O 2013, ' Minimum-norm cortical source estimation in layered head models is robust against skull conductivity error ', NeuroImage, vol. 81, pp. 265–272 . https://doi.org/10.1016/j.neuroimage.2013.04.086en
dc.identifier.doi10.1016/j.neuroimage.2013.04.086en_US
dc.identifier.issn1053-8119
dc.identifier.issn1095-9572
dc.identifier.otherPURE UUID: c60c99c1-0955-4ed0-b5bc-c91a82569df3en_US
dc.identifier.otherPURE ITEMURL: https://research.aalto.fi/en/publications/c60c99c1-0955-4ed0-b5bc-c91a82569df3en_US
dc.identifier.otherPURE FILEURL: https://research.aalto.fi/files/11717344/1_s2.0_S1053811913004333_main.pdfen_US
dc.identifier.urihttps://aaltodoc.aalto.fi/handle/123456789/25843
dc.identifier.urnURN:NBN:fi:aalto-201705114218
dc.language.isoenen
dc.relation.ispartofseriesNEUROIMAGEen
dc.relation.ispartofseriesVolume 81en
dc.rightsopenAccessen
dc.subject.keywordElectroencephalographyen_US
dc.subject.keywordMagnetoencephalographyen_US
dc.subject.keywordInverse problemen_US
dc.subject.keywordMinimum-norm estimationen_US
dc.subject.keywordSkull conductivityen_US
dc.titleMinimum-norm cortical source estimation in layered head models is robust against skull conductivity erroren
dc.typeA1 Alkuperäisartikkeli tieteellisessä aikakauslehdessäfi
dc.type.versionpublishedVersion
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